The detection of dysfunctions, especially in medical devices, is important because the life of the patient may depend on proper functioning of said devices. In case of infusion pumps, for example, the potentially dangerous results of a failure are typically over-infusion or under-infusion of the drug into the patient.
Examples of dysfunctions are leaks, occlusions or presence of air bubbles in the pumping line.
State-of-the-art devices and methods for detecting dysfunctions in medical devices are for instance disclosed in the following patent documents: US 2008/214979, EP 1 762 263 and U.S. Pat. No. 7,104,763.
When using certain drugs, such as insulin, the detection of occlusion may be of particular importance since it is known that catheters may occlude in numerous circumstances. Any such undetected occlusion may result in under-delivery of insulin because it remains undetected for a long period of time. Current occlusion detection devices operate on the piston of the syringe driver and need the building of high pressure inside the syringe before it is detected. Other occlusion detectors consist of pressure sensors situated after the pumping mechanism, on the patient line, which have little sensibility because of e.g. the compliance factor of the tubing line. In certain cases, the absence of detection of an occlusion at the onset of such occlusion result in a high glucose plasma concentration which may appear to the patient as a need to increase its insulin level, resulting in a re-programming of the pump which may result, in the event the occlusion would be suddenly released, in a larger quantity of insulin being suddenly administered with potential serious hazard to the patient.